Among electronic devices, an interior permanent magnet synchronous motor (IPMSM) will be described by way of example, and may be referred to as a motor.
Since the IPMSM simultaneously has a magnetic torque component caused by a permanent magnet and an armature current and a reluctance torque component caused by a d-q axis inductance difference, it may obtain high torque per a unit volume.
However, according to drive characteristics of the IPMSM, excessive iron loss occurs in high speed region, and since a large input current is required to control a high output, copper loss occurs. Such occurrence of a thermal source causes a disadvantage of raising a temperature of the motor, which adversely affect not only a lifespan of the motor but also characteristics of a rare earth based permanent magnet having demagnetization characteristics at a high temperature.
Accordingly, when the motor is designed, it is nature that a consideration on temperature characteristics of the motor should be first applied.
To this end, various thermal analysis technologies of the motor, such as thermal equivalent circuit network method utilizing a lumped parameter method, a distributed parameter method using a finite element method and a finite difference method, and the like have been suggested.
Among these, in order to calculate thermal performance of the motor, the finite element method and the finite difference method are generally used.
However, the thermal analysis using the finite element method and the finite difference method may take a long time to divide the elements and calculate a matrix to analyze a complex region.
That is, there is a problem that it is difficult to apply to an entire region of a shape of the motor.
For this reason, a method is required that a calculation on a thermal analysis is relatively simple and an entire temperature distribution at various portions of the motor may be easily confirmed, as compared to the distributed parameter method.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
The Korean Patent Laid-Open Publication No. 10-2006-0008373 and Korean Patent Publication No. 10-1394548 are related to this application.